The NBA has made two major rule changes ahead of the 2019-20 campaign, one of which is the use of in-game challenge flags similar to that of the NFL.
Unfortunately, NBA head coaches won't simply be tossing red challenge flags on the court, which would certainly be a sight to see. Instead, coaches will simply signal to the referees that they would like to challenge the call on the court.
Sources: The NBA Board of Governors have passed the implementation of in-game challenge flags for head coaches for the 2019-20 season.
— Shams Charania (@ShamsCharania) July 9, 2019
Sources: Head coach’s challenge won’t be a physical flag thrown on the field of play like the NFL — it will be a signal from the coach. https://t.co/4wtdzw2FpN
— Shams Charania (@ShamsCharania) July 10, 2019
Per the NBA's official release (via Tim Reynolds of The Associated Press):
“The first change is the introduction of a Coach's Challenge to trigger instant replay review of a limited set of matters. A version of the Coach's Challenge has been in effect in the NBA G League for the last two seasons and is being used at MGM Resorts NBA Summer League 2019 will be adopted in the NBA on a one-year trial basis during the 2019-20 season.
It remains to be seen how this rule change will affect the game flow and strategies of coaches. However, this is certainly a rule that could benefit teams if used properly.
Moreover, the rule change should also help decrease complaints on NBA refereeing, as the league now somewhat empowers teams to protest a controversial call — something that was prevalent in the past few seasons.